In this prospective study, abruptio placentae and associated haematological and nutritional factors were examined at three large university hospitals in Karachi from January 1990 to December 1992. The incidence of abruptio placentae was 5.0 per cent amongst poor uneducated women and 0.5 per cent amongst women of middle or high socio-economic class. Ninety-five patients with placental abruption who delivered at the Jinnah Postgraduate Medical Centre and Civil Hospital, Karachi, were compared with 150 controls matched for age and parity delivering over the same time. Antenatal anaemia (haemoglobin < 10 g/dl) was found in 67 cases (71 per cent) and 52 controls (33 per cent; P < 0.001). Iron deficiency anaemia predominated, with a strong association with placental abruption (P < 0.001). Protein deficiency was present in 47 per cent of cases and 24 per cent of controls (P < 0.05).